In the fnaf 3 minigame, we see Shadow Freddy or... we do? My theory is that is William Afton wore a Freddy suit. Since William Afton is depicted with the color purple, that makes sense. And also Shadow Freddy has withered parts but this one doesen't.

William Afton approves it

Roxy has collected all the stones (Avengers referance :3)

William Afton's inventory

"OH MY GOD WHAT DO WE DO? WHAT'S THE RESULT OF (2+2 - [65-4]) x ([42+1] + 45-1) ?!?!" (Also yeah I solved the image problem)

Dying is boring even for William

Henry couldn't save her daughter. (STILL )

If bro is true then I am the father of Finding Nemo

I hate it

Theory Golden Freddy:

FNaF 1: "It's me"

UCN: "The one you shouldn't have killed

Film: "Come find me."

If we put these together, it's "It's me, the one you shouldn't have killed. Come find me"

If you find the theory good, please state it in the comments.